Method of partial oxidation of hydrocarbons



in oils from 20 nor-phase process contain Patented Mar. 1, 1938 UNITEDSTATES METHOD OF PARTIAL OXIDATION OF HYDROCARBONS Joseph Hidy' James,Pittsburgh, Pa., assignor to. Clarence P. 'Byrnes, Trustee N 0 Drawing.

Application July 27, 1933,

Serial No. 682,466

9 Claims.

In several patents, including Reissue Patent No. 18,522 of July 12,1932, and several copending applications including Ser, No. 272,567,filed January 22, 1919 now Patent #2085221 and Ser. No. 435,355, filedJanuary 6, 1921 now Patent #2054,- 571, I have disclosed vapor-phasepartial-oxidation of hydrocarbons at relatively high temperatures;especially of the aliphatic or naphthenic type, such as present inmineral, shale oil and the low temperature distillation of coal, whethersaturated or unsaturated; preferably in the presence of a catalyst. Suchmethods have the advantage of extremely rapid attack, a certainpercentage of conversion being obtained in time intervals of seconds orfractions thereof; as compared with hours when carried out in ordinaryliquid phase partial oxidation of the same hydrocarbons.

The complex condensed mixtures from such vaoxygen derivatives rangingfrom alcohols through aldehydes, aldehyde alcohols, ketones, etc. tooxygenated organic acids: and when petroleum fractions are treated,these bodies are present in different molecular weights. There alsooccurs some dehydrogenation and thermal decomposition of highermolecular weight bodies, especially of the oxygenated bodies. I A

Some of the compounds thus formed have peculiar or objectionable odorsand often color; and some bodies present readily polymerize andresinify, thus contaminating certain products such, for example, assoaps when made directly therefrom. Such vapor phase processes may beand have been carried out under subatmospheric, atmospheric andsuperatmospheric pressures, and with one or more catalytic contacts; andwhere more than one contact was used, with addition of more gascontaining free oxygen between such catalytic contacts, and with andwithout steam, or other diluent, such as flue gas. Such processes havebeen usually carried out with temperatures above that of vaporization ofthe oil fraction treated and preferably between 225 C. and 500 C. andnormally between 250 C. and 450 C.

I have discovered that objectionable features of the products of vaporphase oxidation may be overcome and at the same time further oxidationmay be advantageously obtained by sub- J'ecting the condensed productthereof, particularly the oily product which is non-soluble or sparinglysoluble in water: to a liquid phase partial oxidation at a relativelylower temperature I than that in the vapor phase treatment, andpreferably at a considerable or high superatmospherin pressure. Duringthis second step the liquid treated is preferably well agitated, as forexample, by means of the compressed air or other gas containing freeoxygen used in the partial oxidation.

- oxidation, although the product treated is preferably agitated orfinely divided during this step. Due to the opening up or preparatoryaction of the vapor phase oxidation step, the molecules of the productare susceptible to further attack, whether saturated or unsaturated, andobjectionoriginal oxygenated acids are in most cases converted intodibasic acids of good color and odor.

The liquid phase oxidation step may be carried out by the batch systemor continuously. In the following examples, I employed the batch systemusing a pressure reaction bomb having at its top pressures. A two-stageair compressor was connected by a high pressure tubing, having a backseating check valve, to an air tube extending down to near the bottom ofthe bomb within about one-fourth inch thereof. immersed in a suitableliquid heating bath, petrolatum being generally used therefor and keptat a substantially even desired temperature. The capacity of thecompressor at 200 atmospheres gauge pressure was 17 liters of air perminute; and at 150 atmospheres was 8.5 liters per minute. In the firstexample, the material treated was wax distillate treated by my vaporphase catalytic air process above referred to. The oily mixture producedhad a saponification number of 8.52

and contained approximately 27% of saponifiable material by volume.

With the compressor delivering air at the rate of 17 liters per minute,100 cc. of this total oily mixture was treated for thirty minutes at 100This bomb was atmospheres-per sq. in. gauge pressure, at a temliquid ofincreased viscosity about the consisten-.

perature oi. 150 C.

There resulted a recovery of about 96% of oily cy of glycerine, withabout 31% by volume of saponifiabie matter and a saponification numberThe odor was imor 26.20 mg. KOH per gram. proved over that oithematerial oxidized. There was little change in color.

These results show a marked increase in acid content over that of theproduct of the first step.

In the next or second test run, the same raw material was used, allconditions being the same as in run No. 1, except that the time wasdoubled. In this case, the volume recovery was 94%. The saponifiablematter by volume was 50%. The product was an oily liquid somewhat moreviscous than ordinary engine oil and of a brown color. The odor wassweetish with some odor of acetic acid. The saponification number was61.47 mg. KOH per gram.

In the third run, the effect or increasing the air pressure was tried,in a run of one hour, the air pressure being 150 atmospheres gaugepressure per sq. in. The same raw material was used and the sameconditions, as in test No. 1, the air passing up through the liquid at8.5 liters per minute. The result was a thick oily liquid pouring slowlyand of brown color. The odor was sweetish with some odor of acetic andbutyric acids. The volume recovery was the saponifiable matter by volume83%, and the saponification number 105.4 mg. KOH per gram. This test runshowed the best conditions of the runs on the material usedand suchconditions vary according to the particular partly oxidized materialtreated. When the same raw material was treated under the sameconditions as run No. 1, except that the bomb heating bath was kept at200 0., there resulted a slow sooty combustion of the oxidized mixturein the bomb.

In order to compare these above results-with those obtained by applyingthe second step directly to straight hydrocarbons, I used in test No. 4the same conditions as in test No. 1, but ap-' plied this second step tothe original wax distillate used in the vapor phase oxidation to obtainthe material treated in the preceding tests. The result was a volumerecovery of 97%. The product was of a light red color, substantially noodor, saponiflcation No. 1.78 mg. KOH per gram, and saponifiable matterby volume 8%. These results show very slight attack on the straighthydrocarbons of the fraction treated.

In another test, No. 5, I repeated test No. 4, except that thetemperature was kept at 200 C. with a volume recovery of 97%, theresulting oily mixture was of reddish color, the odor. slightly acidic,apparently from organic acids of low molecular weight, thesaponification matter by volume 15% and the saponiflcation number 12.55mg. KOH per gram.

Tests Nos. 4 and 5 show the remarkable'results gained by applying avapor phase catalytic oxidation prior to air pressure oxidation in theliquid phase.

The following runs show the application of my plural step method to akerosene:

' Run No. 6, I used-Venezuelan kerosene, which had been subjected to myvapor phase catalytic air oxidation. This material contained 23% ofsaponifiable matter by volume and its saponification number was 16.38mg. KOH per gram.

Since a preliminary run had shown that a temperature of 150 C. was toohigh at 100 atmosbutyric acids was 94% by volume'ci' an oily. liquid ofreddish orange color, having some odor of acetic and and no aldehydeodor. The saponification matter by volume was 40% and the saponificationnumber was 82.19 mg. KOH per gram.

This sixth run showed that the two-step method is applicable to theproduction of organic acids from kerosene hydrocarbons.

The advantages of my invention result from treating the condensed liquidoxidized product resulting from relatively higher temperature oxidationof hydrocarbons, such as vapor phase treatment, by a lower temperatureor liquid phase oxidation. In this way, the speed oi! obtaining thedesired degree oi oxidation is much increased over that'oi liquid phaseoxidation oi hydrocarbons; while the disadvantages of vapor phasetreatment are reduced or largely overcome. The preparing or opening up"action of the first higher temperature treatment greatly reduces thetime of the second or liquid phase treatment. The mixture treated by thesecond step contains various'oxygen, derivatives of different degrees ofoxidation, each class in different molecular weights, and usuallyunsaturated bodies. In the second step, the further oxidation iseffected at lower temperature, preferably in liquid phase and furtheroxidation proceeds rapidly as compared to. usual liquid phase oxidationof straight hydrocarbons. The objectionable characteristics of theoxidation product treated are also improved. Substantially alloxygenated material is carried over to acids and aldehydic odors areremoved as also those of unsaturated bodies.

The acids produced in the first step may be removed by saponifioation orotherwise before using the second step. The original hydrocarbon usedmay be cracked or uncracked. The temperature and other factors may bevaried in either or both steps, any pressure may be used in the firststep and the superatmospheric pressure maybe varied in the second step.

The product of the first step may be fractioned' changes may be made,without departing from my invention.

I claim:

1. In the method of improving an oily portion of condensed product ofvapor phase oxidation of aliphatic hydrocarbon, the step consisting ofsubjecting said oily portion while in liquid phase to the action of freeoxygen while under pressure on the order of at least 100 atmospheres.

. pheres pressure inthje step: was made at 100 atmospheresg'augepressure and a 2. In the method of improving an oily portion ofcondensed product or vapor phase oxidation of aliphatic hydrocarbon, thesteps consisting of removing acids, .and then subjecting the said oilyportion in liquid phase tothe action of free oxygen while under pressureon the order of at least 100 atm ospheres. 3.- In the method ofimproving an oily portion 5 of the condensed product of vapor phaseendapressure on the order and then fractioning atmospheres.

5. In the method of improving an oily portion or the condensed productof vapor phase oxidagen under pressure on the order of at least 100atmospheres, and supplying oxygen un'der pressure thereto in acontinuous manner.

6. In the method of improving an oily portion and agitating the same bysupplying the said gas under pressm'e.

7. In the method of improving an oily-portion of the condensed productof vapor phase oxidation of mainly aliphatic hydrocarbon, the stepsconsisting of subjecting said oily portion in liquid phase to a gascontaining free oxygen under pressure on the order of at least 100atmospheres, agitating the same by supplying the said gas underpressure, and tapping ofi excess pressure during the treating step.

8. In the method of improving an oily portion of the condensed productof vapor phase oxidation 01' mainly aliphatic hydrocarbon, the step ofsubjecting said oily portion in liquid phase to gas-containing freeoxygen as the sole reactive component while under pressure on the orderof at least 100 atmospheres.

9. In the partial oxidation of mainly aliphatic hydrocarbons, the stepsconsisting of treating the same in vapor or gaseous phase with a gascontaining free oxygen at a relatively lower pressure' and a temperatureof over 250 0., and then treating the same in liquid phase with freeoxygen at a relatively higher pressure on the order of at least 190atmospheres.

JOSEPH HIDY JAMES;

